The invention relates to a filter device for filtering a liquid, in particular, a hydraulic oil, comprising a filter housing having a least one inlet for liquid to be filtered and at least one outlet for filtered liquid, a filter element positioned in the flow path of the liquid between the inlet and the outlet, and a sealing device having a sealing element and a first sealing surface, the sealing element in a sealing position being positioned in a sealing manner on the first sealing surface for sealing off a dirt area arranged upstream of the filter element for liquid to be filtered from a clean area arranged downstream of the filter element for filtered liquid.
The invention also relates to a filter element for such a filter device.
Filter devices of the kind mentioned at the outset are used in a large number of applications in hydraulic systems, in particular, in automotive machines such as, for example, construction machinery or agricultural machines. In particular, mineral oils for hydraulic systems can be filtered with such filter devices. The hydraulic systems have to satisfy very high demands with regard to the cleanliness of the hydraulic oil, so that they can fulfill their function without faults and with little wear over prolonged operating times. Since the filter element gradually becomes blocked with dirt particles during the operating time, it is usually mounted exchangeably in the filter housing. The filter housing may, for example, be of two-part design and have a filter head comprising the at least one inlet and/or the at least one outlet, and a filter pot which is connectable to the filter head with at least one sealing element placed between these. The filter head has an insertion opening through which the filter element is insertable into the filter housing and which is closable by a cover.
The filter element is arranged in the flow path of the liquid between the inlet and the outlet, so that the liquid flowing in through the inlet can flow through the filter element and thereby be filtered and then leave the filter housing through the at least one outlet.
In order to separate the dirt area arranged upstream of the filter element, which receives the liquid to be filtered, from the clean area arranged downstream of the filter element, which receives the filtered liquid, a sealing device is used, which has a sealing element which in a sealing position is positioned in a sealing manner on an associated first sealing surface. The sealing element may, for example, be arranged on an end plate of the filter element. This is known from EP 1 326 693 B1.
During operation of the filter device, the filter element is often acted upon by alternating pressure loads, and it is, therefore, necessary to ensure that the sealing element lies in a sealing manner on the associated first sealing surface.
It is an object of the present invention to further develop a filter device of the kind mentioned at the outset in such a manner that the sealing element also lies reliably on the first sealing surface under alternating pressure loads.